From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.comp.sysutils.supervision.general/2552 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Guillermo Newsgroups: gmane.comp.sysutils.supervision.general Subject: Re: interesting claims Date: Mon, 29 Apr 2019 23:49:24 -0300 Message-ID: References: <11997211556565598@myt6-27270b78ac4f.qloud-c.yandex.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="110482"; mail-complaints-to="usenet@blaine.gmane.org" To: supervision Original-X-From: supervision-return-2142-gcsg-supervision=m.gmane.org@list.skarnet.org Tue Apr 30 04:49:39 2019 Return-path: Envelope-to: gcsg-supervision@m.gmane.org Original-Received: from alyss.skarnet.org ([95.142.172.232]) by blaine.gmane.org with smtp (Exim 4.89) (envelope-from ) id 1hLIpu-000Sej-VB for gcsg-supervision@m.gmane.org; Tue, 30 Apr 2019 04:49:39 +0200 Original-Received: (qmail 14972 invoked by uid 89); 30 Apr 2019 02:50:01 -0000 Mailing-List: contact supervision-help@list.skarnet.org; run by ezmlm Original-Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Original-Received: (qmail 14965 invoked from network); 30 Apr 2019 02:50:01 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :content-transfer-encoding; bh=ziCcg5tz/YSOIvbjuDfHnrcbOHnHSaFiCg8VWef8GAo=; b=mI4FrxO/eaysRxVle9UF8+alVbZJC9B/N6AXupQ27AzQ9EQ7ZUlgRwFbQDgEwGD9Kp a9r7KYAfYuvKL35PBD+1mD7cBv9gMRKXZLgDM+rxwdVmbyVke1T762AST8kwXrQyUtF8 vuHzp2MLpVX7R7QMOzcv+GF5tTzeJBysToKsMglSq0k2bepeol6XjulYqeombkv5Ob3L 5S1nveAQzvBiNmBHxBjgo7X00eyQIHOoGL2RNWOgLR6x/i44jzqjrViSfOYLxNZSxCtv XsLDYiXMw3ryDwLCux0e1yYtcpRexB94jUjg2BXsqAjRtqKuBU6167f9QcjEWbzKtjsw C5Pg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:content-transfer-encoding; bh=ziCcg5tz/YSOIvbjuDfHnrcbOHnHSaFiCg8VWef8GAo=; b=GUzf92tBZ/iHT+JrIMR4oalat3QYQPiTLDAPg46s7sfjzkn4+tH7g8xRFc98gZ/cDQ HAhsmtR/dmsMX+UfHPJX9Zi0vSWStTBy1fdSchEGMafdwOBj8/WiP2SJBC7Hx2AjYWn1 KLWlU5anFp1xuSyHoj/i0L5v6hyMTtGJc76+nQT2Itt75UtJmJ3tgI6tTTfzgzLuC2ph 5S9zkpEY1e9gXiBTT6i1xmliq6yaIR8pKMj4wAEvfOPMQQEKGPT9TRb69CUwLaQB9S8x ec9K6qDHrEopWLB67PwZKBc9Qk+KBBrI9JFBKSWfoJHNcDW/wAjaj6IAoMN1jnTK5XCs xYOQ== X-Gm-Message-State: APjAAAWwXwjjoP+xUx6NqD5bGzheC4lv17MpM9WPcqsg5U7um1VIkoHh OmQgG7TpCSVmRkigDAoEZtU/eoVg13bzHxsrsj6mqA== X-Google-Smtp-Source: APXvYqyHGo7hVDrY44tL/N8K2rvkgJwHnQy49sxQ8Z1X11bDL95e0IjS4tO6eMO00gpI1uM33DP/M7Keu1PoGbKxWfs= X-Received: by 2002:a02:40c8:: with SMTP id n191mr43487033jaa.14.1556592573083; Mon, 29 Apr 2019 19:49:33 -0700 (PDT) In-Reply-To: <11997211556565598@myt6-27270b78ac4f.qloud-c.yandex.net> Xref: news.gmane.org gmane.comp.sysutils.supervision.general:2552 Archived-At: El lun., 29 abr. 2019 a las 16:46, Jeff escribi=C3=B3: > > "suckless init is incorrect, because it has no supervision capabilities, > and thus, killing all processes but init can brick the machine." > > a rather bold claim IMO ! > where was the "correct" init behaviour specified ? > where can i learn how a "correct" init has to operate ? > [...] > there is actually NO need for a "correct" working init implementation > to provide respawn capabilities at all IMO. This was discussed in the mailing list, you'll be able to find relevant messages in the archives, and the last part of the sentence you quoted should clarify what "correct" means in this context. But to recap: * A failure mode is identified (the machine becomes unusable and requires a hard reboot), along with the condition that triggers it (death of all processes except #1). * The condition can be triggered explicitly with a kill(-1, SIGKILL) call in a process with root privileges, so by definition it is not an impossible condition, but this is not the only way to trigger it. Processes can die for a variety of reasons. * An program with "respawn capabilities" running as process 1 can avoid entering this failure mode, a program that does not have the capabilities, cannot. Nothing more, nothing less. This is not a statement about how likely this failure mode is, only that it exists. An init system can or cannot choose to prevent it, this is a design choice (and usage of "correct" will give you an idea of what the author of this particular software package thinks), and a person may or may not decide to use an init system that doesn't, this is a matter of preference. G: